import React, { useEffect, useState } from "react";
import { Stack } from "expo-router";
import { StatusBar } from "expo-status-bar";
import { PortalHost } from "@rn-primitives/portal";
import { GestureHandlerRootView } from "react-native-gesture-handler";
import { Toast } from "@/components/Toast";
import "@/global.css";
import { SafeAreaProvider } from "react-native-safe-area-context";
import {
  View,
  ActivityIndicator,
  InteractionManager,
  AppState,
} from "react-native";
import { useRestoreTheme, NAV_THEME } from "@/lib/theme";
import { SirouRouterProvider, useSirouRouter } from "@sirou/react-native";
import { refreshTokens } from "@/lib/api-middlewares";
import {
  NavigationContainer,
  NavigationIndependentTree,
  ThemeProvider,
} from "@react-navigation/native";
import { routes } from "@/lib/routes";
import { authGuard, guestGuard } from "@/lib/auth-guards";
import { useAuthStore } from "@/lib/auth-store";
import { useFonts } from "expo-font";
import { api } from "@/lib/api";
import { useColorScheme } from "nativewind";

import { useSegments, useLocalSearchParams, router } from "expo-router";

/**
 * GlobalGuard: Handles all routing security and authentication redirects.
 * Reacts instantly to auth state changes to prevent unauthenticated users from seeing protected data.
 */
function GlobalGuard() {
  const segments = useSegments();
  const params = useLocalSearchParams();
  const isAuthenticated = useAuthStore((s) => s.isAuthenticated);
  const sirou = useSirouRouter();
  const [isMounted, setIsMounted] = useState(false);

  useEffect(() => {
    setIsMounted(true);
  }, []);

  useEffect(() => {
    if (!isMounted) return;

    const performGuardCheck = async () => {
      const routeName = segments.length > 0 ? segments.join("/") : "root";
      const isAuthPage =
        segments[0] === "login" ||
        segments[0] === "register" ||
        segments[0] === "otp";

      // 1. FAST AUTH CHECK: If not authenticated and not on a public page, eject immediately.
      if (!isAuthenticated && !isAuthPage) {
        console.log(`[GlobalGuard] Unauthorized on "${routeName}". Ejecting...`);
        router.replace("/login");
        return;
      }

      // 2. GUEST CHECK: If authenticated and on an auth page, redirect to home.
      if (isAuthenticated && isAuthPage) {
        console.log(`[GlobalGuard] Authenticated user on auth page. Sending home.`);
        router.replace("/");
        return;
      }

      // 3. COMPLEX GUARDS: Permissions, roles, etc. handled by Sirou.
      try {
        const result = await (sirou as any).checkGuards(routeName, params);
        if (!result.allowed && result.redirect) {
          console.log(`[GlobalGuard] Sirou Guard Redirect -> ${result.redirect}`);
          router.replace(result.redirect as any);
        }
      } catch (e: any) {
        console.warn(`[GlobalGuard] guard crash:`, e.message);
      }
    };

    performGuardCheck();
  }, [segments, params, sirou, isMounted, isAuthenticated]);

  return null;
}

/**
 * SessionHeartbeat: Proactively refreshes tokens every 5 minutes and upon app foregrounding.
 */
function SessionHeartbeat() {
  const isAuthenticated = useAuthStore((s) => s.isAuthenticated);

  useEffect(() => {
    if (!isAuthenticated) return;

    // Refresh every 5 minutes
    const INTERVAL_MS = 5 * 60 * 1000;

    const performRefresh = async (reason: string) => {
      try {
        console.log(`[SessionHeartbeat] Refresh triggered by: ${reason}`);
        await refreshTokens();
      } catch (err) {
        console.warn(`[SessionHeartbeat] Refresh failed (${reason}):`, err);
      }
    };

    // 1. Initial/Interval Refresh
    performRefresh("Mount"); // Refresh immediately on mount
    const interval = setInterval(() => performRefresh("Interval"), INTERVAL_MS);

    // 2. Foreground Refresh (AppState listener)
    const subscription = AppState.addEventListener("change", (nextAppState) => {
      if (nextAppState === "active") {
        performRefresh("Foreground");
      }
    });

    return () => {
      clearInterval(interval);
      subscription.remove();
    };
  }, [isAuthenticated]);

  return null;
}

export default function RootLayout() {
  const { colorScheme } = useColorScheme();
  useRestoreTheme();
  const [isMounted, setIsMounted] = useState(false);
  const [hasHydrated, setHasHydrated] = useState(false);
  const [fontsLoaded] = useFonts({
    "DMSans-Regular": require("../assets/fonts/DMSans-Regular.ttf"),
    "DMSans-Bold": require("../assets/fonts/DMSans-Bold.ttf"),
    "DMSans-Medium": require("../assets/fonts/DMSans-Medium.ttf"),
    "DMSans-SemiBold": require("../assets/fonts/DMSans-SemiBold.ttf"),
    "DMSans-Light": require("../assets/fonts/DMSans-Light.ttf"),
    "DMSans-ExtraLight": require("../assets/fonts/DMSans-ExtraLight.ttf"),
    "DMSans-Thin": require("../assets/fonts/DMSans-Thin.ttf"),
    "DMSans-Black": require("../assets/fonts/DMSans-Black.ttf"),
    "DMSans-ExtraBold": require("../assets/fonts/DMSans-ExtraBold.ttf"),
  });

  useEffect(() => {
    setIsMounted(true);

    const initializeAuth = async () => {
      if (useAuthStore.persist.hasHydrated()) {
        setHasHydrated(true);
      } else {
        const unsub = useAuthStore.persist.onFinishHydration(() => {
          setHasHydrated(true);
        });
        return unsub;
      }
    };

    initializeAuth();
  }, []);

  if (!isMounted || !hasHydrated || !fontsLoaded) {
    return (
      <View
        style={{
          flex: 1,
          alignItems: "center",
          justifyContent: "center",
          backgroundColor: "rgba(255, 255, 255, 1)",
        }}
      >
        <ActivityIndicator size="large" color="#ea580c" />
      </View>
    );
  }

  return (
    <GestureHandlerRootView style={{ flex: 1 }}>
      <SafeAreaProvider>
        <SirouRouterProvider config={routes} guards={[authGuard, guestGuard]}>
          <ThemeProvider
            value={colorScheme === "dark" ? NAV_THEME.dark : NAV_THEME.light}
          >
            <View className="flex-1 bg-background">
              <StatusBar style={colorScheme === "dark" ? "light" : "dark"} />
              <GlobalGuard />
              <Stack
                screenOptions={{
                  headerShown: false,
                }}
              >
                <Stack.Screen name="(tabs)" options={{ headerShown: false }} />
                <Stack.Screen
                  name="sms-scan"
                  options={{ headerShown: false }}
                />
                <Stack.Screen
                  name="proforma/[id]"
                  options={{ title: "Proforma request" }}
                />
                <Stack.Screen
                  name="proforma/edit"
                  options={{ title: "Edit Proforma" }}
                />
                <Stack.Screen
                  name="invoices/[id]"
                  options={{ title: "Invoice" }}
                />
                <Stack.Screen
                  name="invoices/edit"
                  options={{ title: "Edit Invoice" }}
                />
                <Stack.Screen
                  name="payments/[id]"
                  options={{ title: "Payment" }}
                />
                <Stack.Screen
                  name="notifications/index"
                  options={{ title: "Notifications" }}
                />
                <Stack.Screen
                  name="notifications/settings"
                  options={{ title: "Notification settings" }}
                />
                <Stack.Screen name="help" options={{ headerShown: false }} />
                <Stack.Screen name="faq" options={{ headerShown: false }} />
                <Stack.Screen name="terms" options={{ headerShown: false }} />
                <Stack.Screen name="privacy" options={{ headerShown: false }} />
                <Stack.Screen name="history" options={{ headerShown: false }} />
                <Stack.Screen name="company" options={{ headerShown: false }} />
                <Stack.Screen
                  name="company-details"
                  options={{ headerShown: false }}
                />
                <Stack.Screen
                  name="login"
                  options={{ title: "Sign in", headerShown: false }}
                />
                <Stack.Screen
                  name="register"
                  options={{ title: "Create account", headerShown: false }}
                />
                <Stack.Screen
                  name="reports/index"
                  options={{ title: "Reports" }}
                />
                <Stack.Screen
                  name="documents/index"
                  options={{ title: "Documents" }}
                />
                <Stack.Screen name="settings" options={{ title: "Settings" }} />
                <Stack.Screen name="profile" options={{ headerShown: false }} />
                <Stack.Screen
                  name="edit-profile"
                  options={{ headerShown: false }}
                />
              </Stack>
              <SessionHeartbeat />
              <PortalHost />
              <Toast />
            </View>
          </ThemeProvider>
        </SirouRouterProvider>
      </SafeAreaProvider>
    </GestureHandlerRootView>
  );
}